another life
by airbefore
Summary: The tires chew up the road, carrying him back to the city he escaped from less than two weeks ago. Back to the oppressive heat radiating from the sidewalks and the cold loneliness of an empty loft. Back to the haunted streets, where the ghosts of happy memories and what-might-have-beens lurk around far too many corners. Post season one AU.[Summer Hiatus Ficathon Entry]
1. Chapter 1

**Disclaimer:** All television shows, movies, books, and other copyrighted material referred to in this work, and the characters, settings, and events thereof, are the properties of their respective owners. As this work in an interpretation of the origianl material and not for-profit, it constitutes fair use. Reference to real persons, places, or events are made in a fictional context and are not intended to be libelous, defamtory or in any way factual.

 **AN:** I'm using the ficathon word goal as a way to try to encourage myself to push through the issues I've been having with writing for the past - well, for forever. Fingers crossed.

A note on the timeframe: This story goes AU after the season one finale and is set mid-season three.

* * *

" _There was another life that I might have had, but I am having this one."_

~ Kazuo Ishiguro

He gets an F.B.I. escort back to the city.

Not even the stone-faced silence of the agents flanking him in the backseat of the black SUV can completely extinguish the excitement flickering inside his chest. He's always wanted a police escort, is actually sort of surprised that he's never managed to warrant one before, not even through his most active years of - usually drunken - misadventures. Of course, that was before.

Before he let curiosity get the better of him and managed to screw up what he's pretty sure had the potential to be one of the best things to ever happen to him.

Richard Castle, hands folded in his lap but wrists unshackled, leans forward, mindful of the less than subtle placement of various tools of subdual around the interior of the truck. "Excuse me, Agent Avery," he addresses the solemn young man riding in the front passenger seat. Since he's the only one who has spoken - even if it was only to identify himself and then rather brusquely request Castle's presence in the Escalade idling in the driveway of his Hampton's home - Castle makes the safe assumption that he is the one charge. "Can you please tell me what this is about?"

"You'll find out -"

" -when we get there," Castle finishes for him, the same answer he's gotten each of the last five times. "Not even a hint?"

"No," Avery says, thumbing at the touch screen of his phone and never once sparing a glance in Castle's direction.

Castle slumps back, his shoulder bumping into the meaty bicep of the agent on his right. The tires chew up the road, carrying him back to the city he escaped from less than two weeks ago. Back to the oppressive heat radiating from the sidewalks and the cold loneliness of an empty loft. Back to the haunted streets, where the ghosts of happy memories and what-might-have-beens lurk around far too many corners.

His heart sinks when they pull up outside a too-tall building, the mid-afternoon sun glinting off the countless windows and making him squint. Avery tucks his phone into the breast pocket of his suit jacket and slides out of the SUV, his lean body fluid and graceful. The back door pops open and the beefy armed agent, moving far too quickly for a man of his size, thumps down onto the sidewalk. A jerk of his dimpled chin has Castle scrambling out after him, tripping over his own flip-flop clad feet as he stares up at the eerily signage free facade of the building that houses New York City's F.B.I. Headquarters.

"Let's go," Avery commands, striding toward the front door.

Castle watches the reflection of the SUV in the glass as it pulls back out into traffic and then follows. The flip-flops slap against his heels, the noise echoing loudly in the library quiet of the lobby. The chill of the industrial grade air conditioning cuts through the thin cotton of his vintage Green Arrow t-shirt and cargo shorts, brings up goosebumps on his exposed forearms and calves. A security guard looks him over from his post behind a bank of black and white monitors, a smirk tilting the corners of his mouth. He really should have insisted on being allowed to change.

"Okay, we're here," Castle points out, standing off to the side as Avery swipes his badge across the electronic pad of the elevator. The doors glide open and they both step in. Avery presses the tip of one long, thin finger to the button for the eighth floor, his dark skin going two shades lighter under the pressure. "Am I allowed to know what the hell is going on now?"

Avery stares straight ahead, the reflection of his stoic face made wavy by the brushed metal of the elevator doors. "The SAC will explain what you need to know momentarily."

"What I need to know?" Castle repeats, annoyed at his own incredulousness. "What I _need to know_ is why the F.B.I. showed up at my summer home in a black SUV with tinted windows - which, by the way, could you guys be more cliche with that?- and forced me - "

"No one forced you, Mr. Castle," Avery says, his voice as placid as his demeanor. "We merely requested your cooperation. The decision to comply was yours alone."

"Requesting cooperation while brandishing a weapon pretty much guarantees compliance," Castle huffs.

"A Bureau issued sidearm secured in a holster is not a brandished weapon," Avery clarifies and Castle swears he can hear just the slightest waiver of a chuckle behind the words. Son of a bitch is actually enjoying this.

"Look, _Agent_ -"

A subdued ding announces their arrival on the eighth floor. The elevator glides to a smooth stop, the doors sliding back into their pockets to reveal a bustling but oddly quiet bullpen. Men and women roam about, all dressed in various shades of black and dark blue and speaking in hushed, hurried voices. Phones ring and keyboards click, but all at a muffled decibel, as though they know that this is a serious environment and their joyful noise would not be appreciated.

A pair of agents stand in front of an opaque glass square mounted against the far wall, conversing in whispers as they look at a box filled with scrolling text. The female agent reaches out and touches the glass, stopping the words. With a flick of her finger, she moves the box to one corner of the screen and then pulls up three more boxes, each of varying sizes and content.

" _Whoa_ ," Castle whispers, awed in spite of himself. "That is so cool. Where can I get one?"

"Government issue, Mr. Castle," Avery says, more of the barely restrained amusement in his voice. "This way."

Castle trails along after him, walking as slowly as he thinks he can get away with. His eyes dart around the room, cataloging details, trying to make as vivid a mental picture as he can. The urge to write settles almost uncomfortably at the base of his neck, a heavy feeling that tenses the line of his shoulders and seeps down into his arms. His hands curl into loose fists, ready to unfurl over a keyboard and fly.

Avery comes to a halt and Castle, head still craned around to catch the last glimpses of the bullpen, almost walks into him. He mumbles an apology but Avery ignores it, his hand already twisting the handle on a door marked 'Interview 3'. The heavy wood slab swings inward and Avery motions for Castle to follow it.

"You're not coming?" Castle asks, shame burning hot across the back of his neck. Adrenaline, intrigue, and a healthy dose of annoyance have carried him this far but the idea of crossing that threshold and facing whomever or whatever is waiting for him without Avery makes him feel like a scared little kid unsure of why he's been called to the principal's office.

All he gets from Avery is a shake of the head. Okay. Alone it is. Sucking in a deep breath, Castle pulls himself up to his full height and steps into the room. Two women sit with their backs to him, their heads angled together in conversation. The door closes with a soft whoosh and snick and the room falls silent. The woman on his right stands and turns to face him, the tips of her auburn hair brushing across the collar of her fitted suit jacket.

"Mr. Castle," she says, her voice husky and lower than he would have guessed, "I'm Special Agent in Charge Jordan Shaw. Thank you for joining us."

"I was under the impression that declining your invitation wasn't really an option," Castle rebuts, taking her extended hand and shaking.

"No, it wasn't," Shaw agrees, the left corner of her mouth quirking up. "But I appreciate it all the same."

"So are you going to tell me why I'm here now or do I have to start guessing? Because if it's the latter, I'm definitely going to need to consult a lawyer before I end up incriminating myself."

The woman still seated at the table snorts, her hands busy closing and arranging files, and he feels the knot of fear in his chest loosen.

"No need to request your one phone call, Mr. Castle," Shaw says. "You're here as a consultant, not a suspect. We have a killer who is using your books as the basis for his murders and -"

"Again?" The question pops out before he can stop it and Shaw's eyebrows raise. "Sorry," he says, trying to wipe it away with a wave of his hand. "It's just that this happened a few years ago -"

"Harrison Tisdale," Shaw interrupts. "Yes, I'm aware. The NYPD reports that you were instrumental in solving that case and I'm hoping you'll prove just as valuable an asset this time."

Castle feels his chest puff. Instrumental. She must have talked to Montgomery, then. Not -

Yeah, definitely Montgomery.

"I'll help however I can."

"Good," Shaw says, turning to pull out her chair. She waves Castle around to the other side of the table. "And on the topic of the NYPD, I believe you're familiar with our other consultant on this case, Detective -"

"Beckett," Castle breathes, coming up short when he rounds the table, his heart lurching hard against his ribs.

Beckett looks up, her expression - once upon a time an almost open book to him - unreadable. Her hair, long and caramel colored now, curls around her face and shoulders, shining even under the harsh fluorescent lights, and he has the insane urge to wind his fingers through it, test the silky texture of his memory against reality. He can see the glint of a necklace through the open collar of her button up shirt and the guilt he's never completely suppressed swirls to life in his gut, making his stomach churn.

"Castle," she says after a moment, nodding toward the empty chair on his side of the table. "Sit down."

Eyes never leaving her, Castle gropes in midair for the back of the chair. When his fingers finally curl around the cold metal frame, he drags it out and sits, landing off center. The edge of the seat digs into the meat of his left thigh, but he can't stop staring at Beckett long enough to care. His brain keeps overlaying the image of the last time he saw her - the wild look in her eyes, the kiss bruised pout of her lips, her short hair splayed out across the pillowcase in soft spikes as she came apart underneath him - and he finds himself suddenly unable to draw in a full breath.

"You grew out your hair," he mutters and Beckett dips her chin, eyes darting down to where her hands are folded together on the table top.

The loud clearing of a throat makes him jump. Castle tears his eyes away from the flush creeping up Beckett's neck and looks toward Agent Shaw. The smile ghosting across her lips makes him feel like a teenager and all he can do is shrug. Shaw nods.

"As I was saying, the two of you know each other."

"Yeah," he says, reduced to monosyllables as his gaze gravitates back to Beckett.

"Mr. Castle assisted my team with the Allison Tisdale case," Beckett says, her voice far too even for his liking. And his ego. Couldn't she be thrown just the _tiniest_ bit off her game by his presence? "After which he began to shadow my team's cases as research for -"

"I know, Beckett," Shaw cuts her off with a short laugh. "And I'm fairly certain Mr. Castle remembers the sequence of events as well."

"Vividly," he pipes up, glad to have regained the ability of polysyllabic speech.

Beckett still won't look at him so he keeps staring at her, eyes tracking over and over every visible inch. Time has drawn its hand over her face, chiseled the soft roundness of her cheeks and jaw into sharp angles. He wants to trace them, feel the hard bite of her bone against the fleshy pads of his fingertips, prove to himself that she's here. Real. He'd truly never expected to see her again. Not after that morning when he'd woken up naked and alone, the signed copy of Heat Wave he'd sent to her resting next to him on the cold sheets.

One night.

Kate Beckett had been in his bed for one glorious night. One night that was at once more than he'd ever really let himself believe they'd have and not even close to being enough.

"Since we're all up to speed on your previous relationship with Detective Beckett and the NYPD - " Agent Shaw says, and Castle watches the pink stain on Kate's neck crawl even higher at her use of the R word - "let's talk about why you're here now, Mr. Castle."

"You said someone is basing murders off my books."

Shaw nods. "Specifically, the books you wrote about Detective Beckett."

"Nikki Heat," Beckett interjects. "The books are about Nikki Heat, not me."

Castle sees Shaw roll her eyes in his periphery. "The Heat character is based off you, Beckett," she says, the weariness in her voice indicative of an argument had one too many times. "Which is the exact reason we're all here."

"Wait, what?" He finally drags his eyes away from Beckett to focus on Shaw. "What do you mean?"

"Our suspect is obsessed with Nikki Heat," Shaw clarifies, hooking a thumb toward Beckett. "He's committed two murders so far, all in the name of catching Detective Heat's attention. He wants her to play with him."

"Shit."

"Precisely," Shaw agrees.

"What can I do?"

Anything. He'll do anything.

"We've already contacted your agent," Shaw informs him, "and her office is sending over your fan mail. What we need from you is insight." Castle cocks his head in silent question and Shaw continues. "This man wants Nikki Heat. With the combination of you and Detective Beckett, we can give that to him. Use it to draw him out."

Castle flicks his gaze back to Beckett, watches the muscles in her jaw flex. "Beckett," he whispers, pleads. For the first time since he sat down, she looks directly at him. Their eyes lock and it knocks the air out of his lungs. It's still there, all of it. The hurt, the anger, the spark he's only ever felt with her. God. It'll be a miracle if he survives this.

"I'm in," he says, still looking at Beckett but directing his words toward Shaw. "Where do we start?"

The door opens and he looks up, watching as a team of agents file through, each carrying a cardboard box stuffed with envelopes. The boxes pile up, a half a dozen of them, before the last agent walks in and drops his load directly in front of Castle on the table, the metal legs vibrating with the impact.

"Where we start, Mr. Castle," Will Sorenson says, his eyes cold and voice dripping with disdain, "is with your adoring fans."

"Sorenson." Castle looks up at him, fighting against the urge to stand up. To put them on equal footing. "What - I thought you worked kidnappings?" He drops his eyes back to the women sitting across from him. "Has someone been taken?"

Shaw shakes her head.

"I have a special interest in this one," Sorenson explains, a smirk curling the corners of his mouth as he steps up and places a hand on the back of Beckett's chair, "seeing as how it involves my wife."

* * *

 _Thank you for reading. Your thoughts and comments are always appreciated._

 _Much gratitude to Kate and Allison for the beta work and cheerleading._


	2. Chapter 2

**AN:** Two quick notes because there were a few questions in the reviews: This is AU after the Season 1 finale, meaning that the reason Castle is no longer at the 12th is because Beckett kicked him out for looking into her mother's case, just like in that episode. And the timeframe for this universe is early to mid Season 3; I moved the Shaw case around becauses it was a good arc to use to bring Castle back but I needed it to occur later than it did in canon. Hope that clears things up.

* * *

The chairs in the conference room are uncomfortable. Supposedly built for lumbar support, the overstuffed seats and thin, open weave back leave her longing for her chair at the Twelfth. Years of use have left those cushions molded to the contours of her body, a perfect cradle for her sore joints and aching muscles through long hours of phone calls and paperwork. Beckett suppresses the urge to shift, unwilling to put herself at even more of a disadvantage. She cannot afford to be weak. Not here. Not now.

Not with _him_ sitting across the table, staring at her over the top of a wrinkled piece of notebook paper.

Beckett keeps her head down, eyes locked on the letter held in her gloved hands. She knows there's nothing in it but she scans the looping cursive script for a third time anyway. Completely over the top and fawning, but innocuous. Beckett slips the page back into its powder blue envelope and tosses it on the growing pile of discards. Castle clears his throat and she ignores him, reaching into the box on the floor next to her chair and fishing out yet another envelope.

"I have the strongest sense of deja vu right now. I mean, your hair is longer but you still have that adorable pinched, angry thing working face-wise. It's oddly comforting."

A beat passes. Two. Three. When she doesn't answer him, Castle folds up the letter she knows he didn't even read and stuffs it back into the envelope, all pretense gone.

"Come on, Beckett," he says, voice just this side of whining. "You can't ignore me forever."

No, she can't.

But she can try.

"I suppose congratulations are in order," Castle persists, the whine in his tone having been replaced by something she can't quite name. Something hard and sharp. "Or is it best wishes? I can never keep that straight."

"Your mother would be appalled," Beckett answers, surprising herself.

Giving in for just a moment, she looks up at Castle, lets herself really see him. The lines around his eyes have lengthened over the past two years, stretching almost to his temples when he gives her a sly grin. She can see finger tracks through his unstyled hair and her stomach clenches hard at the memory of the only other time she's seen him that way, how the softness of his hair against her palms contrasted so deliciously with the rough scrape of his stubble on her thighs. Crossing her legs, Beckett drops her gaze back to the papers spread out on the table in front of her.

"It's best wishes for the bride," she says, willing her eyes to focus on the lines of neat block printing, "congratulations for the groom."

Castle snorts out a laugh. "Pretty sure the last thing the groom wants is my congratulations." The rustling of paper fills the air as he tugs a new letter out of its envelope. "How long -"

"About a year and a half," Beckett answers before he can finish.

"When did he -"

The door swings open and Shaw strides through, open file held aloft. "We got a name and address," she announces. "Let's roll."

Becket strips off the gloves and wipes her sweaty palms on her slacks as she pushes back from the table and stands. Castle bounces out of his seat, face lit up with little boy glee.

"Not you," Beckett says, pointing at him and ignoring the twinge in her chest when his smile melts into a pout. "You stay here and keep going through these letters."

"Oh, come on," Castle argues. "We both know there's nothing to find here. If this guy is as fixated on you -"

"Nikki Heat," she mutters.

" - as you say, then we all know there's no way he contacted me," he finishes, ignoring her interjection. "This," he waves a hand at the boxes, "is a waste of our time."

"He's right," Shaw cuts in. "A couple of junior agents can handle the fan mail. Mr. Castle, you're with us. Let's go."

"I call shotgun!"

Castle nearly claps his hands as he follows Shaw out of the room, his t-shirt stretched tight over the breadth of his upper back. Beckett takes a deep breath and closes her eyes, counting down slowly from ten. Her shoulders open as she exhales, body held upright and rigid. She can do this. One case, no more than a week. Then he'll be gone and she can go back to -

"Beckett!" Shaw bellows. "Time is of the essence here."

The weight of the badge and gun at her hip comfort her as she strides down the hall, the sound of her heels muted on the thin industrial carpeting. Shaw and Castle board the elevator and Beckett follows them in, arms crossed loosely over her chest as she leans back against the corner of the compartment. The elevator deposits them on the garage level and they file out, Shaw leading the way.

"Do we have time to stop by my place so I can change?" Castle asks, reaching for the handle to the passenger door of Shaw's SUV. "I have a feeling that flip flops aren't the best footwear for a take down."

Becket shoots him a look as she slides past, batting his hand away from the door handle and popping it open herself. "Y _ou_ aren't going to be anywhere near a take down," she tells him, planting a foot on the running board and hoisting her body up.

"I called shotgun," Castle reminds her with a pout.

"Badge trumps shotgun," she tosses back, pointing toward the rear of the truck with her free hand and smothering a grin as he makes an indignant noise in the back of his throat. "Get in."

"So bossy," Castle mumbles, hauling himself through the open back door. "Nice to know some things never change, I guess."

* * *

"Put the taser _down_ ," Shaw bites out, her mouth a firm line of disapproval and annoyance.

Castle huffs from the back seat and Beckett has to raise a hand to her mouth to stifle a laugh. Shaw cuts her eyes in Beckett's direction, hooking a thumb over her shoulder. "He always like that? Grabby?"

Heat floods her chest and Beckett drops her hand back into her lap. She rubs her left thumb against the base of her bare ring finger, swallowing thickly before answering, a forced lightness in her tone.

"I've tried my best to suppress the majority of it -"

"Hey!" Castle pipes up from the back. "Rude."

"- but from what I recall, yeah. He touches things."

"And you put up with that for how long?"

"You know I can hear you, right? That you ignoring me doesn't mean I've gone deaf?"

Beckett stares straight out the windshield, one shoulder lifting up in shrug. "He was surprisingly helpful," she says, proud of herself for the level of indifference she manages to inject into the words. "I had my doubts - frequently - but like I told you, he was instrumental in solving that first case -" she ignores the tiny gasp from the backseat - "and the handful he worked after that did benefit from his involvement."

Shaw hums next to her. Beckett refuses to look over. Or back. She keeps her gaze trained on the entrance to the building they are supposed to be watching, her spine straight and face blank.

"So," Shaw drawls out, "how long were you sleeping together?"

Becket tenses, one hand curling into a tight fist in her lap. She will not react. Will not let this woman rile her up, throw her off her game. Keeping her tone flat and even, she answers, "We weren't."

Shaw scoffs. "Give me a break, Beckett."

"No, she's right," Castle pipes up, his voice light and airy. "We weren't sleeping together. Aside from my second marriage, it was the most sexless relationship I ever had."

Shaw opens her mouth to respond but -

"We've got movement," Beckett says, already reaching for the door handle.

The front doors of the SUV swing open and both women quickly slide out. Shaw points back at Castle before slamming her door. "Stay."

"Can I at least get the window cracked?"

Beckett hits the button on her door panel and the back window on Castle's side glides halfway down. She risks a look at him, finds him watching her with shrewd eyes. "Thank you," she mumbles, hating herself for it even as the words leave her mouth.

"Don't mention it, Beckett," he shrugs, a bitterness in his voice that leaves her mouth dry and chest tight. "It was the truth. One night doesn't exactly count as sleeping together , does it?"

Not trusting her words, Beckett gives him a sharp nod and shuts the door, unholstering her weapon and heading for the pack of agents standing on the corner. He's right. One night doesn't really count.

At least it wouldn't if she hadn't already been engaged.

* * *

 _Thank you for reading. Your thoughts and commets are always appreciated._

 _Gratitude to Allison for the enthusiasm and Kate for the red ink._


	3. Chapter 3

The F.B.I. long ago outgrew two sided mirrors, so Castle watches the interrogation on a closed circuit feed two rooms down. He wanted to go in with them, to be in the thick of it, but one raised eyebrow from Shaw had him scuttling down the hall like a chastised child. He sits in a squeaky chair at a scratched conference table, attention focused on the flatscreen monitor in front of him and wishing the camera was angled toward the two women rather than Donald Salt.

"So I was on one of those internet barter sites, and I was looking – It, uh, doesn't matter what I was looking for." Salt waves his bandaged hand through the air, batting away the unasked questions. Castle shudders at the thought of what this greasy creep might have been trolling the internet for. "But I came across the ad. 'Finger wanted. Will pay top dollar.'"

"And what's top dollar for a pinkie finger?" Beckett asks.

Salt holds up the bandaged hand again, the remaining fingers spread wide and a twisted sort of excitement in his tone when he answers, "Five thousand bucks."

"Sounds like a real deal," Shaw scoffs and Castle grins.

He likes her. Her no nonsense attitude and the dry humor paired with what appears to be a wicked sharp mind appeals to him. Intrigues him a bit. He doesn't get from her that same spark of inspiration that he feels with Beckett, isn't compelled to attempt to capture her in words. But he does like her.

"Hey, you get less than that for a kidney," Salt tosses out like it should be common knowledge. "So anyway, I emailed him back. Told him I had everything he wanted."

"You gave him the finger," Shaw says with what Castle imagines to be a smirk. "What else did he want?"

"He wanted me to have a violent felony conviction and to be recently paroled. And you also had to be willing to suffer through the indignity of a false arrest." Salt leers in Beckett's direction and Castle feels his hackles rise. "He told me Detective Nikki Heat would be coming for me, and it might get _physical_." Salt's face shifts, becomes harder, the amusement sliding off the corners of his downturned mouth. "He didn't mention anything about Captain America with the taser gun."

Castle can't stop the smirk from unfurling across his lips. He had so very much enjoyed that; jumping out of the back of the SUV and stunning the shit out of this loser. His enjoyment had been short lived, though, the bubble of adrenaline in his chest bursting as soon as Salt starting mouthing off about 'Detective Heat'.

"So he warned you that he would be planting your fingerprint at a murder scene," Beckett surmises.

"Which is why you have an alibi," Shaw continues.

Salt gives them both a shit eating grin. "I was perched on my favorite bar stool at McSorley's until closing every night since that man took my digit and walked away with it in his cooler."

"Is this the man?" Shaw asks and Castle assumes she's showing Salt the artist's sketch from the witnesses at Grand Central Station.

Salt barely spares her a glance. "I'm not sure. Didn't really see him. He had a hat and sunglasses."

Beckett leans forward, her head tilted slightly to the right. Castle feels his own body canting forward. He knows that head tilt. Saw it many times throughout their brief partnership. She's onto something.

 _Man_ , he's missed watching her work.

"Who bandaged your finger?"

Salt grins at her, a sick sort of pride in the creases around his beady eyes. " _He_ did. He said you'd notice." Beckett reaches out, her fingers plucking at the loose end of the shoddy bandage. "Oh be gentle with me, Nikki," Salt faux simpers, licking at his dry lips.

Castle's hands curl into tight fists on the table. What he wouldn't give to taser this asshole again.

"She has to deal with that kind of shit all the time now," a voice says from behind him. "Thanks to you and your ridiculous books."

The chair squeaks loudly when Castle spins around. Sorenson leans against the wall, hands stuffed in his pockets and resentment in his eyes.

"It was never my intention to make her job more difficult," Castle says. This man will not be getting an apology from him.

Sorenson scoffs. "So you thought writing a character - who you've made _known_ was based on her - as a slut who spends more time on her back than solving crimes would make her job easier?"

Castle grips the padded arms of his chair, squeezing the foam until his knuckles blanch. Fire, fast and all consuming, blazes in his chest. Words, so many words, tangle at the base of his throat, charred and hot, burning the insides of his cheeks when he finally chokes them out.

"Have you even read them?" he asks, the question a low growl that he barely recognizes as his own voice.

"What?" Sorenson asks, chin jerking up as if he's been punched.

If only.

"Heat Rises and Naked Heat. The books I wrote. The books your _wife_ -" he almost spits the word, wants to wash the bitter ashes of it out of his mouth -"inspired. Have you read them?"

"Why the hell would I do that?" Sorenson laughs, dry and humorless.

"Why - Why would you -"

The door swings in, the sharp leading edge catching Sorenson in the shoulder. Castle tries and fails to squash the juvenile thrill he gets from watching Agent Square Jaw stumble like a sleepy toddler. His amusement fades quickly when he looks at Beckett's face.

"We've got something."

* * *

For all their technology, the FBI's coffee sucks. Castle stands in the breakroom, a paper cup of tepid black sludge clutched in his hand. He doesn't need the caffeine. His blood still buzzes with the high of breaking the coded message from Salt's bandage, standing sandwiched between Shaw and Beckett in front of the smart board, the three of them tossing theories back and forth like a baseball.

The roar of pride in his chest when he broke it, figured out that the numbers corresponded to his first Nikki Heat novel, only served to make him realize just how much he's missed this. The pace and the challenge. The sense of accomplishment and the knowledge that he's been helpful. That he's done something _good_. Something tangible and meaningful. The cases he'd worked with Beckett and the NYPD had changed him in ways Castle thinks he's only just beginning to see.

An angry hiss in the hallway catches his attention, and Castle steps into the doorway only to slink back when he realizes who that hiss belongs to. He hates himself a little for skulking in the shadows to watch this little drama unfold, but getting insight into the Beckett-Sorenson marriage isn't an opportunity he's willing to pass up.

"You might as well have dropped your pants and peed a circle around me," Beckett bites out, her arms crossed tightly over her chest, fingers gripping her own biceps. "It was humiliating."

"Oh, come on, Kate," Sorenson scoffs, one shoulder braced against the wall and his back to Castle. "It's not a big deal."

"It is to me," Beckett says, her voice that low, dangerous tone that Castle only remembers hearing twice in the time they spent together. "Shaw is already judging me because of the Nikki Heat stuff - you've heard the cracks she's been making- and the last thing I need is my _husband_ acting like a jealous idiot. Don't make this harder for me, Will."

"No, that's his job, right? Him and his goddamned books"

"Jesus Christ," Beckett sighs. "Are you ever going to let it go?"

"Are you ever going to admit that you love the fact he's still writing about you after all this time?"

Silence hangs in the air, and Castle swears he can feel the wave of Beckett's anger rolling down the hallway. She breathes deeply through her nose, head tilted back to expose the long line of her neck.

"Kate- " Sorenson cajoles, his tone contrite but still too sharp, the ragged edge of bitterness stubbornly clinging on.

Beckett holds up her hand. "Don't. I'm not having this fight with you again. Not now, not here." She finally lowers her chin, looks at her husband with a sad resignation. "You should go. Your team is waiting."

Sorenson doesn't argue, doesn't try to smooth things over or explain. He pushes off the wall and leans in, presses his lips to Beckett's cheek. "I should be back in a couple of days. Don't stay here all night."

Beckett nods. She stands in the hall for close to a minute after Sorenson walks away, her hands clenching and releasing on her biceps. Castle watches her exhale and roll her shoulders back, her spine lengthening as she pulls herself up to her full height. Beckett spins on her heel and marches away, her stride confident and sharp.

* * *

He finds her holed up in a tiny office down the hall from Shaw's bustling war room. Perched on the edge of a rickety old metal desk, Beckett stares at the map of subway routes she's tacked to the wall with blue and red push pins.

"It's not a grande skim latte with two pumps sugar free vanilla," he says, holding out the paper cup of coffee with a smile, "but it is hot and caffeinated."

Beckett gives him a tight grin and takes the cup, the tips of her fingers brushing over his knuckles for half a second. "Thanks, Castle."

Taking a huge risk, Castle stands next to her, closer than they've been all day, and leans against the empty half of the desk. She doesn't move, doesn't acknowledge his closeness in any way. He decides to count it as a win.

"What are you looking for?" He asks, pointing at the map.

"Subway routes," Beckett says, grimacing around a sip of coffee. "Trying to see if I can trace a pattern from Grand Central to the carousel to the next location."

"And?"

"And I can't." She huffs out a breath, her cheeks ballooning with force of it. "There's nothing."

She looks exhausted and stressed, the purple shadows under her eyes so deep that they stretch almost all the way to the apples of her cheeks. Beckett turns the coffee cup around and around in her fingers, the nail on her left pinky tapping against the bottom rim. He watches her hands and finds himself wondering yet again why she's not wearing a wedding band.

"Maybe Shaw can get her team to analyse the map with their computer systems," Castle offers.

Beckett barks out a sharp laugh that startles him. "I'm sure she could."

"Should we ask her?"

"The whiteboard - or wall - has always worked just fine for me." Beckett cuts her eyes in his direction and Castle feels a sharp stab somewhere in the vicinity of his stomach. "Plus, since the two of you are so _brilliant_ together, she's busy tracking down and interviewing those morticians."

Beckett looks away, her focus back on the wall. Castle stares at her profile, the sharp jut of her chin and the way the muscles in her jaw clench and release. Confusion mixes with anger in his gut, bubbling up and making his chest burn with acid. He won't apologize for being helpful. For working with Shaw to figure out every possible lead.

"Beckett, we need to -" Castle starts, and she shakes her head at him.

"Not now, Castle."

Castle clenches his own jaw. The rose colored lenses he's remembered her through for the past two and half years suddenly turn clear. This was always her way, shutting him down and out at every turn. Even when all he was trying to do was help. He knew that the feelings he harbored for her had never completely left him and he's quickly come to understand that that includes the frustration and annoyance.

"When, then?" He asks her. "And don't make a joke about my inadvertent rhyme."

The light laugh she gives him, barely more than a huff of air, soothes some of the burn inside his chest. "Just - later, Castle, okay?" She looks over at him, her eyes tired and skin pale. "Later."

He nods. This isn't the time or the place. He's aware of that. They stare at the map together, the air between them no longer tense but not quite at ease either.

"Maybe," he says, desperate to be helpful to her in some way, "there's something about the way he chooses his victims? First a man, then a woman."

Beckett tilts her head, considering his idea, and then shakes it. "A lawyer and a dog walker? No. There's no way to predict where he's going next." She twists her arm to peer at the oversized watch on her wrist. Her father's watch. Castle's heart trips a little at the sight of it. "And it's already nine. We're out of time. He's going to kill again, all in the name of Nikki Heat."

Avery walks through the office door just as Castle opens his mouth to say something - anything - to try to convince her that this isn't her fault. If anyone is to blame, it's him. He's the one who wrote the damn books.

"Beckett," Avery says, his voice something animated for the first time since Castle met him. "War room, now. He's on the phone."

Beckett hops up and jogs after Avery. Castle pushes himself off the edge of the desk with a sigh. He allows himself five seconds of silence then grabs Beckett's mostly full coffee cup from the scratched wooden desktop, tossing it in the garbage as he heads out the door.

* * *

 _Thank you all so much for the entusiastic response to this story so far. The follows and favorties and especially the reviews mean the world to me. And, as always, thank you for reading. Your thoughts and comments are appreciated._

 _Much thanks to Allison and Kate for helping to make this story better than could ever manage alone.._


	4. Chapter 4

_How does it feel to know that you have failed?_

The words play on a loop in her head. Beckett crouches by the pool of drying blood, her hands gripping her ankles in an effort to keep herself from lashing out. From pounding her fists against the concrete until her leather gloves are nothing but shreds, her knuckles broken and bloody. She failed. She didn't catch him. Doesn't even have any idea who he is.

She failed and now another woman is dead.

Shaw barks out orders, her voice echoing in the mostly empty parking garage. Agents move around in hurried silence, collecting the bullet casings and snapping pictures of the scene. Shaw says something about interviewing the attendant and Avery strides off, the tail of his suit jacket fluttering.

"Hey." Castle squats down next to her. "You okay?"

Beckett laughs, a dry and brittle noise that breaks apart against her teeth. "Just fuckin' peachy, Castle."

"Beckett," he says in a too soft voice and she has to close her eyes against the memories it invokes. The antiseptic smell of a hospital hallway and the pitying look on his face. The smooth satin of his sheets and the way his hands felt running over her flushed skin. "This isn't -"

Bracing her hands on her knees, Beckett pushes herself up and walks away. Shame wraps a fist around her stomach and she ignores it, pushes through the urge to turn around and apologize to him. She can't. Not if she wants to maintain even the illusion of composure.

Castle scrambles after her as she approaches Shaw. "What do you need from me?"

"Go home," Shaw says.

"That's - No."

"Yes, Beckett," Shaw asserts, looking up from the notepad in her hand and fixing Beckett with a withering stare. "There is nothing you can do here."

"I can canvas," Beckett argues. "Or review tape."

"My people are handling that," Shaw tells her and Beckett doesn't miss the proprietary phrasing. It hits her harder than she'd thought it would, knowing that Shaw still doesn't consider her one of the team, and Beckett sways a little on her tired feet. "You're no good to me if you're burned out," Shaw continues, her tone a few shades softer. "I need you in the game. Go home and relax. Get some sleep."

Logically, she knows Shaw is right to send her home. She's been going at this thing non-stop for three days. Hasn't been back to her apartment since the morning the first call came into the Twelfth reporting the murder at Grand Central. She's already gone through the backup outfit she keeps at the precinct and the one from the trunk of her car. Lanie had to bring her fresh clothes this morning, her face set in a disapproving frown when Beckett met her on the sidewalk outside the FBI Headquarters and didn't have a satisfactory answer for why her husband wasn't the one bringing her underwear and her favorite heels, the ones that make her feel invincible.

"This isn't necessary," she argues one last time, knowing it's futile.

Shaw simply looks at her and shakes her head. "Go home, Beckett."

With a reluctant nod, Beckett spins around. She's halfway across the parking garage before she realizes she has no way home. Esposito took her cruiser back the Twelfth yesterday, and even she isn't crazy enough to take public transportation or a cab when a serial killer is stalking her. Beckett turns back and finds one of the junior agents and Castle following her.

"I got put in time out too," Castle tells her with a one shouldered shrug. "Agent McVickers is gonna take us both home."

McVickers gives her a stiff nod and walks past, heading to the closest of the SUVs. Beckett heads for the truck and pops open the rear door just as the agent starts the engine.

"Opening doors for me, Beckett?" Castle holds a hand over his heart and gives her an exaggerated sigh. "And they say chivalry is dead."

Ignoring him, Beckett climbs into the backseat and slams the door. She's not in the mood to be observed right now, to have McVickers monitoring her from the driver's seat as they trek across the city. Her armor has taken a direct hit and she can feel it crumbling to pieces around her, leaving her vulnerable. Open to attack. She hates what this case has done to her.

What seeing _him_ again has done to her.

The front passenger door opens and Castle slides in, then gets back out to retrieve the flip flop he lost. Beckett closes her eyes and leans her head against the window, hopes the shadows will conceal the way her hands shake in her lap.

* * *

She takes her gun into the bathroom while she showers.

Paranoia wraps around her like a cloak, shields her skin from the cleansing blast of hot water and steam. No matter how she scrubs, she can't penetrate it, can't get through to reach the layers of guilt and shame. She gets out of the shower feeling dirtier than when she stepped in, her skin red and body weary.

She stares at herself for a long time in the foggy bathroom mirror. The purple stains under her eyes, the way her bottom lip is chapped and raw in one corner, the sharp points of her cheekbones. She looks like hell warmed over and it pisses her off. Makes her angry and even more resentful of Shaw and how she's managed to remain put together, not even a single hair falling out of place during the many hours of research and casing and chases.

Growling, she spins away from the vanity, refuses to look back as she combs through her wet hair and works it into something resembling a braid. Pulling on a pair of yoga pants and a ragged old Stanford t-shirt, Beckett grabs her weapon from the back of the toilet and stomps out of the bathroom, relishing the wave of heat rising in her chest. She'll take anything over the helplessness.

She eats dinner hunched over the kitchen counter, the cold pasta and chicken clogging her throat and sitting like a stone in her stomach. A half-full bottle of wine whispers to her from the second shelf of the fridge but Beckett ignores it, reaching instead for the pitcher of filtered water. She gulps down two glasses and realizes for the first time just how thirsty she was, that she hasn't really put much into her body other than stale pastries and burnt coffee from the FBI breakroom over the past three days. She'd asked Will to bring her something real for dinner last night but he'd forgotten, apparently too caught up in his petty anger over the official decision to bring Castle in as a consultant to care about the needs of his wife.

Pouring out a third glass of water, Beckett sighs. She's being unfair to him. She knows he's worried about her and that he was only trying to help when he suggested that Castle would be an hindrance rather than an asset. He honestly believed - believes - that. Will has never understood that, for all his faults, Castle was helpful during the time he spent at the Twelfth. That he provided her team with insight and ideas they wouldn't have arrived at on their own, at least not in time. His theatrics and theories were over the top but she always knew that when it came down to it, she could count on him. Trust him.

Or at least she thought she could.

Gun and glass in hand, Beckett makes her way into the living room, eyes flicking over to double check the locks on the front door. She plops down on the couch and trades the gun for the remote. Fifteen minutes and countless cycles through the channels later, she gives up. The TV shuts off with a soft click and she tosses the remote back onto the coffee table, curls herself up into a ball in the corner of the couch. Her toes flex against the soft fabric and she stares down at them, the baby blue paint on her nails chipped. Briefly, she contemplates repainting them, spending a mindless hour clipping and filing and painting, losing herself in the mundanity. But the idea passes as quickly as it came and she looks away, chin propped up on her knees.

Her eyes scan the apartment, lingering on the shadows, the places where she can't quite make out the details. Discomfort sparks along her nerve endings and Beckett huffs out an annoyed sigh. She will not let this happen, will not let this psycho make her feel like a victim inside her own home.

Feeling like a failure is already victory enough for him.

The bookshelf catches her gaze and she feels herself leaning toward her lifelong coping mechanism. Reading has always been her first choice for relaxation. For clearing her head and losing herself when the real world becomes too much to bear. She can't read the titles from her vantage point but she knows the ones she's looking for - the ones she needs - aren't there.

Unfolding from the couch, Beckett shuffles on sore legs over to the corner of the living room that serves as her home office. Will took over the actual office when he moved in, claiming that he would be bringing work home more often than she. He wasn't wrong but the memory of coming home to find her desk and computer shoved into the darkest corner of the living room still pisses her off two years later.

She flicks on the antique lamp, the stained glass shade throwing prisms of color across the wall, and squats down next to the desk. Her hamstrings protest the position but she relishes the burn as she reaches for the bottom drawer on the left side. The brushed metal handle feels cool against her skin when she curls her fingers around it and tugs. Her heart kicks up a notch when the first spine comes into view, the title and his name printed in raised letters on the glossy paper. Beckett stares at them for a long moment, shame and anger fighting for dominance in her chest.

The books sat proudly on her shelf for years, a collection that grew by increments until she had them all, a rainbow of hardcovers to choose from on the nights when her job - her life - was too much and she needed an escape. Even after she met him, after he started following her around and annoying her, after he broke her trust and betrayed her - after all of it, his words were still her first choice for comfort. She could still lose herself in them, the warmth and humor and the idealistic notion that justice always prevails.

She shouldn't have to keep them hidden in a drawer, have to sneak to read them when her husband isn't home. But she does, and it leaves her feeling guilty and angry every time. Will refuses to accept that the books are not the man and after too many arguments over it, she gave in and moved them just to make it stop. Slid them into a drawer one afternoon while Will was at work, let him believe that she had gotten rid of them completely. It was easy. Just one more lie to add to the list.

Beckett draws a finger over the row of spines, reading and dismissing titles as she goes. She puts on a show for herself, tries to pretend like she doesn't know which one she's going to end up with. She knows. But this is what she does now. This is her routine. She goes down the line, touching each book and reviewing the plot in her head, delaying the inevitable. She always gets there in the end, though, her fingers curling around the one she knows almost from memory by now.

Heat Wave

The one he wrote about her.

The _first_ one he wrote about her. She has the second book - a copy she bought because he didn't send her one that time, which, despite the little stab of pain in her stomach when she thinks about it, she knows was for the best - but it doesn't speak to her in the same way. She's not sure why. Maybe because he wasn't around when he wrote it. Maybe because the wound he left her with wasn't as fresh and raw when she read it. Maybe because Nikki Heat became less like Kate Beckett with every turn of the page.

A creak from the hallway distracts her before she can extract Heat Wave from the drawer. Beckett spins on the balls of her feet, keeping herself in a low crouch. She shuffles back toward the coffee table and grabs the gun before rising up to her full height. Her apartment sits at the end of the hall and the unit opposite is currently unoccupied. She knows Will won't be coming home tonight so there is absolutely no reason why anyone should be outside her front door.

She spares a glance back at her cell phone on the end table, knows she can't waste valuable time going back for it now. Releasing the safety on her weapon, she flips the deadbolt open as quietly as she can then grips the bronze plated handle and turns. The door swings in suddenly and she raises her gun, pointing it directly at the shrieking man in her hallway.

"Castle?! What the hell are you doing here?"

Lowering his hand from in front of his face, he gives her a sheepish grin, the one that makes her heart skip a beat. Castle holds up his other hand, shows her the DVD case he's clutching with white knuckles.

"Movie night?"

Beckett stares at him. He's changed clothes since McVickers dropped him off at the loft a couple of hours before, traded the shorts for jeans and the t-shirt for a blue button down. She kinda misses the t-shirt.

"How do you even know where I live?"

Castle's grin goes from sheepish to wolfish in a second. "Oh how quickly we forget, Detective." He waves the DVD at her, the title a blur. "Bippity boppity boo."

She sighs. "I could have moved since then."

"But you didn't," Castle says, inching forward. "Now are you going to invite me in or leave me out here as serial killer bait?"

Beckett moves to the side, waving him in with her free hand. She locks the door behind him and engages the safety on her gun, carrying it with her back over to her desk. Kneeing the open drawer closed, she flicks off the lamp and turns back to face him. Castle stands in the middle of her living room, eyes dancing from one thing to the next.

"What do you want, Castle?" she asks.

He looks toward her, eyes roaming from her head to her feet and back again, and Beckett remembers her current state of dress. He's never seen her like this. He's seen her naked - once, she reminds herself, just once - but never wearing anything other than her work clothes. Her armor. Beckett curls her toes into the rug, resists the urge to wrap her arms around her middle.

"Agent Shaw said to relax," Castle says, holding up the DVD again. "What better way to relax than with an animated classic?"

"Well, if Agent Shaw said so," she bites out. "And cartoons? I think you have me confused with my fictional counterpart."

"Ha! I knew you read them."

"Of course I read them." His face lights up and she rolls her eyes to keep from smiling. "Had to see whether or not I needed to sue you for defamation."

"Ouch, Beckett." Castle clutches a hand over his chest and pouts at her. "That hurt. And what did you mean 'If Agent Shaw said so'?"

She shakes her head. "Nothing."

"No, really. What did you mean?"

Beckett sighs. "Just - I see the way you are with her. The way you listen to her and fawn -"

"I do not fawn," Castle argues.

"- over her and her toys. Used to be the murder board was enough- " used to be _she_ was enough - "but now you need a smartboard?"

Castle stares at her for a moment, head cocked to the side. "You're jealous," he says, obviously delighted.

Of course she is. But damned if she's going to let him know that.

"No, I'm embarrassed. I vouched for you. Told Shaw that you could be an asset to this investigation. Now here you are, acting like a kid in a candy store every time you see a new gadget. It's -"

"Embarrassing," he finishes for her, smiling. "You said."

"Just - Rein it in, okay?"

Castle nods, exaggerates a solemn expression. "I'll try to be more sedate."

"Thank you."

Three days worth of exhaustion hits her out of the blue, her body suddenly heavy and weak. Beckett sways a little on loose ankles and Castle starts toward her, hand outstretched. She waves him off and he stops short, eyeing her carefully. "Maybe we should put the singing rodents off for another night," he says. "You look like you're about to drop."

Beckett nods at him, too tired to even attempt to hide it. She plods toward the door, setting her gun down next to her phone on the end table as she goes. Hand on the knob, she turns back to find Castle stretched out on her couch, shoes off and an arm bent behind his head, his broad shoulders almost too wide for the depth of the cushions.

"What the hell do you think you're doing?"

"Getting comfortable," Castle says, shifting his hips. She has to look away, heat blooming low in her abdomen. "You have a spare pillow I can borrow? This couch is seriously deficient in the stuffing department."

"The couch is fine," she breathes, lacking the energy to even attempt to raise her voice. "And I'm sure you'll find all the pillows you need at home."

Castle looks up at her, something dangerous in the set line of his mouth. Her throat goes dry as he sits up, his eyes dark and locked on hers. "I have more than enough pillows," he says, the unspoken _and you know it_ coming through loud and clear. "And I'll gladly get back to them tomorrow. Tonight, I'm staying here."

"Why?" Beckett asks, blaming lack of sleep for the shake in her voice.

"To protect you."

She laughs at that. "With what? Your vast arsenal of rapier wit?"

Her heart kicks hard against her ribs as he stares at her, storm clouds brewing in the depths of his eyes. Castle leans forward, one elbow propped up on the back of the couch, and speaks to her slowly. "There is a madman gunning for you because of _me_ , Beckett. I'm not leaving you alone."

"Will -"

"Isn't here," Castle cuts in.

"No," Beckett says, leaning back to let the door support her weight, "he's not. But he _is_ my husband."

Castle laughs, the sound sharp and jarring in the stillness of her apartment. "Your husband who couldn't even be bothered to stick around while his wife is being stalked by a serial killer." She opens her mouth to rebut that, to defend Will and his work, but Castle plows on, the bitterness in his voice softening with sincerity. "I'm not here to wreck your marriage, Kate." Her stomach rolls at the sound of her first name in his mouth. "I'm just - I'm trying to help. Let me at least feel like I'm doing _something_ for you, okay?"

Beckett meets his eyes, sees the need and the hurt and - so very many things. Things she doesn't want to think about. Can't. Because if she does - if she lets herself remember, lets herself feel -

"Okay," she agrees, pushing off the door. "You can stay. But only for tonight." As quickly as her tired body will allow, she crosses the living room. Beckett turns back at the threshold to the hallway, finds Castle watching her. She swallows, her throat thick, and points at the hope chest on the far wall. "Spare pillow and blankets are in there."

He nods, unmoving. "G'night, Beckett."

"Night," she returns before turning away, her legs burning with the urge to bolt. To run as fast and far away from him as she can.

The bedroom door closes behind her and Beckett falls back against it, sinking down to the floor and hugging her knees tightly to her chest. She stares at the unmade bed, at the pillow where her husband's head should be.

Fuck.

* * *

 _Thanks so much for reading. The support for and interest in this story warms my heart. As always, your thoughts and comments are greatly appreciated._

 _Gratitude once again to Kate for the red ink._


	5. Chapter 5

Castle gives up on the idea of decent sleep around the tenth time he jerks awake, body rising up off the lumpy couch cushions as though they've suddenly been electrified. Fishing his phone out of the back pocket of his jeans, he sighs. Six. He sits up, hissing when the side of his foot collides with the scarred wooden leg of the coffee table. Hanging his head low, Castle stretches out his neck, wincing at the painful pull of knotted muscles. This couch was not made for sleeping.

He wonders if Sorenson knows that. If he has first hand experience with waking up on this couch, his body one big ache and Beckett on the other side of a closed door.

Pushing the thought out of his head, Castle stands and stretches, swallowing down groans of pleasure as the tense muscles in his back start to lengthen and release. He lifts his arms over his head, twists at the waist, bends over to touch his toes. Blood sings through his veins as his body comes alive, unraveling limb by limb. With one final twist, hands braced against the wall for leverage, he feels a satisfying pop in his lower back and lets out a quiet moan.

Gauzey grey light spills through the skylights in the living room, and Castle stares up, watching the gradually brightening sky. He loves the early morning, when the world still feels sleepy and cozy, the moon reluctant to cede the stage to its brighter co-star. It does something to him, watching as the stars fade from view. Makes him feel an odd sort of peaceful melancholy, touches the place inside his chest where the words grow. He loves to write in the hours just before dawn, the story unfurling inside his head as the sun slowly creeps over the horizon.

He wants to write. Now. Has felt the intense burn of need since the moment he first laid eyes on her again, his already smoldering fingertips igniting. He's been jotting down sentences and ideas whenever he can, scribbled on napkins or hastily thumbed into the notes app on his phone when he thought no one was looking. His mind churns with it, with her. Them. Beckett and Nikki. The both of them more real to him than they have been in months.

And now, here, in her home and surrounded by her scent and her things, he can't stop himself. He has to write, has to get the words out before he either loses them or his brain simply explodes from the overload of images and ideas.

Bypassing the loathsome couch, Castle heads for the squishy looking armchair tucked into a corner next to the bookcase. He tugs his phone back out as he sits, types in the passcode. His notes are scattered and would be nonsensical to anyone other than Castle, but he's able to piece them together quickly, the plot coalescing in his mind. His thumbs are clumsy on the touchscreen and Castle growls in frustration as the autocorrect feature tries to make sense of his errors. He finally gives up and just types, letting the misspellings and random corrections happen. He can figure it out later.

After thirty minutes of feverish writing, the well runs dry. Castle copies what he's written and pastes it into an email to himself. He's never fully trusted technology, especially not since he spilled a glass of pinot across his laptop and lost half a novel. He checks his email, making sure the copied text has arrived safely in his inbox, and then puts his phone to sleep.

He needs to call Alexis and check in, make sure that Meredith hasn't spirited her away to a foreign country or tried yet again to convince her to take a meeting with an agent. But it's still the middle of the night in California so he tucks the phone back into his pocket and leans his head back against the high back of the chair. The stuffing molds easily around his skull, cradling it, and he breathes deeply, content. He should have slept here, not on that wretched excuse for a couch.

His eyes wander, taking in the space. Sunlight, stronger now, drips down the walls, throws highlights across the hardwood floor. He follows the path of a beam that slices down the middle of the living room, cutting it into two almost equal pieces. The light ends at the bookcase, a natural sort of spotlight for the rows of spines and assorted knick knacks. Standing, Castle walks over to the unit, trails the tip of one finger over the rounded edge of a shelf as he scans the titles. Classics mingle with non-fiction and bestsellers, biographies share space with travel guides and slim volumes of poetry.

The sinking of his heart when he doesn't see his own name, not even once, feels inevitable. Of course she doesn't have them. Whatever enjoyment she may have once derived from his work must be long dead by now, killed by the betrayal she could never forgive, no matter how much or sincerely he apologized. By trying to help her, he lost her. Lost whatever they could have had, which he still can't help thinking had the potential to be one of the greatest things to ever happen to him. Or her.

His only comfort - as petty as it may be - comes from the fact that of the few picture frames on display, none contains an image of Sorenson. No candid shot, no posed formal portrait. Nothing from their wedding or a vacation. Castle might not have a place on these shelves, but neither does the man she married.

Spinning on his heel, he looks around the room again, paying closer attention to the details. The crocheted afghan tossed over the back of the couch, the quirky arrangement of artwork on the walls, the desk and corkboard tucked into the far corner of the room. All of it hers. He's never been in her space before but he knows. Everything - from the wooden elephant figurine on the side table to the shaggy rug under the coffee table - belongs to Beckett.

He doesn't see a single piece of her husband anywhere.

* * *

Having a dead body fall on his socked feet is really not Castle's ideal way to start a morning. Agents fill Beckett's apartment, recording the scene with pictures and notes scribbled in those tiny, pocket-sized notebooks he has never understood the appeal of. Beckett stands in the kitchen with Shaw, her oversized sleep shirt hanging off one shoulder and her bare toes curling against the blue tile. With her arms crossed over her middle and hair falling out of its braid, she looks something like a recalcitrant child in the middle of a scolding.

"Didn't expect to see you here."

Castle turns to find Avery standing next to him, his perfectly pressed suit identical to the one from yesterday. "Yeah, I was -"

"Making breakfast," Avery says, inclining his head toward the mess scattered across the kitchen counter. "Pancakes, by the looks of it."

"It was all she had ingredients for," Castle defends.

Avery hums in the back of his throat, the corners of his mouth quirking up. "It's a little too intimate, if you ask me" he says, amusement in his tone. "Pancakes, coffee, you. A married woman."

"Nothing happened," Castle grinds out.

"I'm sure," Avery nods, still smirking. "But it's going to make for a very interesting scene report all the same."

An agent with a camera calls for Avery from the hallway, and he walks away without another word. Castle takes a moment to breathe deeply, eyes closed and hands fisted at his side. He has spent enough time with Avery now to have learned that the man hides a wicked sense of humor behind his stone faced facade. He knows the agent was just messing with him, trying to get a rise.

But the implication behind the joke, the sharp bite of truth buried in the humor, bothers him. Offends him. In spite of the reputation he may have in some circles, Richard Castle does not cheat. Not from either side of the equation.

Taking one last cleansing breath, Castle opens his eyes and unclenches his fists. This is not the time for - any of it. He heads toward the kitchen, his shoulders set and mind clear. It's time to work.

* * *

 _Nikki will burn_

Acid churns in his stomach and Castle finds himself grateful that they never got around to having those pancakes. Pictures of the spent slugs hang suspended on the smartboard, the translucence making them seem almost innocuous. A search runs in another opaque box, lines of text scrolling past too quickly for him to read. It all spins inside his head, leaving him dizzy. Castle leans against the wall, eyes closed, as he tries in vain to find his equilibrium.

Nikki will burn.

Fuck.

* * *

Castle sits in the backseat of Shaw's SUV again, his hands clasped together in his lap, left thumb rubbing a circuit around the knuckle at the base of his right. Every instinct he has screams at him, tells him that this is wrong. But he doesn't speak up, doesn't allow himself to break the tense silence that fills the inside of the truck.

They park in the staging area down the block from Ben Conrad's apartment building, nosing into the middle of the fleet of FBI issued sedans and SUVs. Shaw's phone rings just as she shifts the truck into park and he can see her smiling in profile as she answers it.

"Hi, sweetie," Shaw says, her voice so much softer than he ever imagined it could be. "How was school?"

A tiny, tinkling voice comes from the phone, the words too quiet to make out but the excitement understandable all the same. His heart clenches, aching for the loss of hearing that same kind of rushed little girl joy from his daughter. Castle tugs his phone out, the need to connect with his kid, even if just digitally, overwhelming him. He sends her a text, tells her that he loves her and hopes she's having fun with her mom. Jokingly offers to send her on another vacation to recover from this one once she gets home.

"That's so great, sweetheart," Shaw says, true happiness in her voice. "I'm very proud of you but Mommy's gotta go arrest somebody now. I'll be home for dinner and we can have ice cream for dessert to celebrate, okay?" Shaw pauses for a moment and then laughs. "Yes, I'll get the kind with the marshmallows. I love you. Okay. Bye bye."

The smile fades off Shaw's lips as soon as she ends the call. She slips the phone into her vest and unbuckles her seatbelt, face set. Beckett unbuckles her own belt, shifting in her seat.

"You're a mom?" she asks Shaw, and Castle thinks he hears something that might be wistfulness in her voice.

"Yeah," Shaw answers, not even bothering to look over at Beckett. "And you can holster your gun, Detective. You're both staying here."

"What?" Castle rocks forward, hands flying up to grip the front seats as he wedges his upper body between them. He looks from Shaw to Beckett and back again, finds the same grim look of determination on both their faces. Anxiety wells in his chest. Sitting in the car for this just feels wrong. "Come on, Agent Shaw. You can't -"

"She's right," Beckett says, determination sliding into resignation. "I'm his target. I can't compromise her team by walking into the line of fire."

Shaw nods at them both and reaches for her door handle. "I'll send someone for you as soon as it's clear."

Castle slumps back into the seat. "This sucks."

Beckett doesn't respond, just stares out the windshield, her nails tapping out a syncopated rhythm on the center console. He wants to talk to her, wants to ask if she thinks this is right, that they have the right man, if she doesn't think this is all just a little too neat and tidy.

But he doesn't.

"She's a mom," Beckett murmurs, her voice barely audible.

"What?"

She shakes her head. "Nothing. I just never pegged her for a parent. I thought she was like - "

The ringing of her cell interrupts. Castle has the insane urge to grab it from her and throw it out the window. He needs to know the end of that sentence, needs to know who or what she thought Shaw was like. Like her? Like Sorenson?

"Beckett," she answers, her voice sharp. "What? Put him on."

She's out of the car before Castle can blink, phone held to her ear as she jogs toward the swarm of agents approaching the entrance to the apartment building. Castle scrambles after her, the hair on the back of his neck prickling. He catches her in the middle of the sidewalk and steps in close. So close he can smell her perfume, feel the tension vibrating in her muscles. Beckett tilts the phone toward him, the backs of her fingers brushing against his cheek.

"Ben," Beckett says as they both stare up at the silhouette of a man pacing back and forth in front of a window, a gun held tightly in his left hand. "You're surrounded. I need you to put down the gun and step out of your apartment."

 _"That's not our game, Nikki. One of us has to die."_

Even in the sweltering humidity of a warm August day, the voice sends chills down Castle's spine.

"No one has to die," Beckett asserts, taking a half-step toward the building. Castle wraps his fist around the back of her bulletproof vest, determined to hold her back. To not let her run headfirst into the line of fire.

" _Someone always has to die! And since it can't be you-"_

Beckett yells as the man in the window raises the gun to his head before stepping out of sight. The report of the shot surprises Castle and he rocks back on his heels, pulling Beckett off balance as he goes. Their bodies collide and she looks over her shoulder at him, a fire in her eyes that makes him release his hold on her vest, his entire body burning. Beckett breaks for the building, her heels clattering on the pavement, and Castle follows after her, pulled by some invisible rope that he finds himself wishing he could sever.

* * *

 _Goodbye, Nikki. Goodbye, Nikki._

Castle stands next to Ben Conrad's desk, the recorded voice from the detonator playing on a loop in his mind. He stares at the pile of disassembled electronics and schematics, hands balled into fists to keep himself from reaching out and picking them up. The scene plays out in his imagination: Beckett's cruiser blowing apart in an explosion of metal and glass, the fireball that would have engulfed the parking garage at the precinct, the piles of rubble and columns of black smoke.

There would have been nothing left of her. No body to identify, no remains to claim. Nothing but ashes, impossible to distinguish from the debris. The thought makes tears prickle in his eyes.

"Castle."

Her voice startles him, the reality of her colliding with the images in his head and making him jump. Castle spins around, heart hammering in his chest. Beckett stares at him, her head cocked to one side. He barely resists the urge to swipe at his face, to make sure that no trace of his irrational grief has leaked out.

"You okay?" Beckett asks, her narrowed eyes searching his.

"Fine," he says, waving a hand back at the desk. "Just - He had quite the finale planned."

He watches her eyes flick past him and then back, the long, pale line of her throat working as she swallows. "Yeah. He did."

"I'm glad we got him before -" Castle raises his fisted hands in front of his chest and then pops his fingers out in a crude pantomime of an explosion.

Beckett chuckles, her shoulders loosening. He smiles at her, watches the way the corners of her mouth rise and fall as she fights a grin. "Me too."

"And the best news is, I'm out of your hair. Again."

Her lips fall into a flat line once more, all traces of humor gone as she looks up at him with a guarded expression. "No," she says and Castle feels his heart kick hard against his ribs. "The best news is that it's over."

* * *

Ben Conrad.

The name doesn't fit. Logically he knows it's just his penchant for the dramatic, his desire for a good story, but it just doesn't _feel_ right. Serial killers aren't named Ben Conrad. It's too generic, too forgettable. Too easy.

Castle looks over the copies of the crime scene photos he charmed out of a junior agent while Beckett and Shaw weren't paying attention. Conrad's lifeless eyes stare at the camera, his right elbow bent and fingers still wrapped around the handle of the gun. Something isn't right. It's all too neat, all the evidence lining up so very perfectly to point them in the direction of the dead man in the picture.

His cell phone buzzes across the desktop as it rings, Alexis' smiling face glowing on the screen. Castle swipes his thumb across the green arrow and picks it up, spinning around to put his back to the pictures as he greets his daughter.

"Hey, Pumpkin," he says, leaning back in the chair, "How's the Golden State?"

"It's good," Alexis chirps, the brightness in her voice instantly perking him up. "Spent the day shopping with mom. She has an audition tomorrow that she claimed to have nothing to wear for."

Castle hums, suspicious. "This audition isn't just another one of her plans to get you into a meeting with her agent, is it?"

"I think she's given up on that," Alexis tells him. "At least for this trip. Right now she's all about trying to talk me into getting matching tattoos."

Laughter bubbles up inside his chest, the first real joy he's felt in two days. "Ooo, what cliche is she suggesting? A butterfly on your ankle? Chinese symbols on your lower back?"

"Close. She wants infinity symbols on our wrists."

"Ah," he says, nodding. "Meredith's gone hipster."

Alexis giggles and he smiles. "I keep trying to explain to her that even though tattoos are more socially acceptable now, I can't go on college interviews next year with a tattoo on my wrist. I mean, can you imagine me trying to hide that while shaking hands with an Ivy League admissions officer?"

Castle sits up and spins back to face the desk, his brain kicking into overdrive. He tucks the phone into his shoulder and rifles through the papers scattered across the desk. Hands. That's it.

"Alexis, I'm gonna have to call you back, 'kay?"

"Are you okay, Dad?"

"Yeah," he assures her, trying to keep the panic out of his voice. "I'm fine. Something just came up that I need to deal with."

"Okay," Alexis says, her voice wary. "Call me later. Love you."

"Love you too, Pumpkin."

Castle grips the phone with white knuckles as he stares down at the desk. The bruising pattern on the second victim. The handwriting. The man in the window. All left-handed. But Ben Conrad was shot on the right side. Impossible. If Conrad was the killer, he would have shot himself with his left hand. Castle brings up the contact list on his phone, presses Beckett's name as he runs for the front door.

* * *

The adrenaline crash hits him two hours later. Castle leans up against the side of the ambulance, his hands shaking. Blue and white lights flicker all around him in a strange strobe effect. His shoulder aches, a dull, splintering pain that keeps him grounded, keeps his mind from wandering too far into the dark forrest of what might have beens.

Someone hands him a bottle of water and he downs it in three gulps, his throat still burning from the heat and smoke. The paramedics tried to look him over but he'd just passed Beckett to them, waved off their insistence that he needed treatment. He wasn't the one who just barely survived an attempt on his life by hiding in a bathtub.

He saw her. In the few seconds before she yelled at him to turn around, he saw. The burns and cuts on her back, the trails of blood snaking their way over her sooty skin. The gash at her hairline, the slice across her left kneecap. He knows it could have been worse, that she's lucky to be alive but - He saw. He knows. It's worse that she's going to let anyone see. Especially him.

The rear doors of the ambulance swing open and Castle stands up straight, shakes off the exhaustion creeping up his spine. He watches as the paramedic helps Beckett down the metal steps, her body swallowed up by the too big sweatpants and FBI windbreaker he managed to scrounge up for her. Beckett sucks a breath in through her teeth when her left foot hits the ground and Castle looks down, sees the elastic bandage wrapped around her ankle. He hadn't been able to find any shoes for her, so there she stands in a pair of thin black socks he stripped off his own feet.

Shaw strides over, her mouth set in a grim line. "Tell me what you saw when you came home."

Beckett closes her eyes, swaying a little on the spot. He wants to step in, tell Shaw to back the hell off. But he won't. He can't.

"The, uh, the doors were locked like I left them. The windows were shut. And - I don't know." Beckett blows out a frustrated breath and opens her eyes to look at Shaw. Lights flash over her face in a hypnotizing pattern, turning her expression from stone to silk and then back again. "Nothing seemed out of place but I don't know because I thought the case was done."

Shaw nods. "It's not, but you are."

Beckett's spine goes straight and he watches as she morphs from a shocked, injured woman into a fierce, determined cop in the span of a second. "No," she growls, the smoke inhalation giving her voice a depth that makes his toes curl from equal parts fear and desire. "This is my apartment. My life and my case. You're not benching me on this, Shaw."

"Fine," Shaw agrees after a tense staredown. "Your life, your case, but _my_ rules. You do what I say when I say and how I say it."

Beckett gives a terse nod of understanding. "Deal."

"She needs a security detail," Castle says.

Shaw and Beckett pivot to look at him, both of them seeming to have just realized he's there. "He's right," Shaw agrees.

"It's not necessary," Beckett argues, glaring at him. "I'll be fine."

"Yes," Shaw nods, "you will. Because my men will be with you at all times."

The fire chief, a tall man with kind eyes and a thin mustache, approaches the ambulance, cutting off Beckett's rebuttal. "Fire's out and the structure is secure," he announces, looking back and forth between Beckett and Shaw. "You can go up when you're ready."

"Let's go," Shaw commands.

She spins and marches away, her stride long and efficient. Beckett starts to follow, stepping carefully around the piles of debris still littering the sidewalk. Castle lingers behind her, ready to reach out. To catch her. Carry her. Help.

"Kate!"

Beckett looks up, her head swiveling toward the group of cops and spectators. Castle follows her line of sight, his eyes scanning the crowd.

"Kate!"

Beckett moves toward the voice, her socked feet splashing through puddles of water as she breaks into a limping jog. Sorenson slips past the barricade, badge held high over his head as he runs. He catches Beckett up in his arms, lifts her into a crushing hug. Beckett presses her cheek against her husband's neck, clinging to him.

Sorenson stares up at what used to be his home, his face a mask of fear and anguish. Beckett's shoulders shake and he drops his gaze, focuses instead on the woman in his arms. He whispers to her, lips pressed to the shell of her ear as they sway together in the middle of the street.

Castle watches them for a moment and then turns away, his sockless feet slipping inside his shoes as he makes his way into the smoldering remains of the apartment building.

It's not over.

* * *

 _As always, thank you for reading. Your thoughts and comments are welcome and appreciated._

 _Thanks to Kate for the editing and Alex for the writing pom poms._


End file.
